Valve system for a hydraulic emergency travel gear function of an automatic transmission for a motor vehicle

Abstract

A valve system for a hydraulic emergency driving gear function of a hydraulic control unit for a motor vehicle automatic transmission includes a position valve (104) with a first piston slide (120) and an electromagnetic pressure regulator (86) having a decreasing characteristic curve. The first piston slide (120) is preloaded in a first position. When the first piston slide (120) is in a second position, the electromagnetic pressure regulator (86) is configured for connecting a system pressure-carrying line (18) of the motor vehicle automatic transmission to a first emergency driving gear clutch (12) of the motor vehicle automatic transmission and to a second emergency driving gear clutch (15) of the motor vehicle automatic transmission, whereby the first emergency driving gear clutch (12) and the second emergency driving gear clutch (15) are actuated, so that an emergency driving gear of the motor vehicle automatic transmission is engaged.

The invention claimed is: 
     
       1. A valve system for a hydraulic emergency driving gear function of a motor vehicle automatic transmission, comprising:
 a position valve ( 104 ) with a first piston slide ( 120 ); 
 an electromagnetic pressure regulator ( 86 ) having a decreasing characteristic curve; and 
 an OR valve ( 85 ), 
 wherein the first piston slide ( 120 ) is movable into a first position and into a second position, and the first piston slide ( 120 ) is preloaded in the first position, 
 wherein, when the first piston slide ( 120 ) is in the second position, the electromagnetic pressure regulator ( 86 ) is configured for connecting a system pressure-carrying line ( 18 ) of the motor vehicle automatic transmission to at least one first emergency driving gear clutch ( 12 ) of the motor vehicle automatic transmission and to a second emergency driving gear clutch ( 15 ) of the motor vehicle automatic transmission such that the first emergency driving gear clutch ( 12 ) and the second emergency driving gear clutch ( 15 ) are actuated to engage an emergency driving gear of the motor vehicle automatic transmission, and 
 wherein the OR valve ( 85 ) is configured for hydraulically connecting either the first emergency driving gear clutch ( 12 ) or the second emergency driving gear clutch ( 15 ) to the position valve ( 104 ) such that the first piston slide ( 120 ) is hydraulically pressurized and moves into the second position against the preload. 
 
     
     
       2. The valve system of  claim 1 , further comprising an emergency operation valve ( 103 ) with a second piston slide ( 133 ), wherein:
 the second piston slide ( 133 ) is movable into a first position and into a second position, and the second piston slide ( 133 ) is preloaded in the first position; and 
 when the first piston slide ( 120 ) is in the second position, the electromagnetic pressure regulator ( 86 ) is hydraulically connected to the emergency operation valve ( 103 ) via the position valve ( 104 ) and is configured for hydraulically pressurizing the second piston slide ( 133 ) in a non-energized condition such that the second piston slide ( 133 ) moves into the second position against the preload to connect the system pressure-carrying line ( 18 ) to the first emergency driving gear clutch ( 12 ) and to the second emergency driving gear clutch ( 15 ), whereby the first emergency driving gear clutch and the second emergency driving gear clutch are actuated to engage the emergency driving gear of the motor vehicle automatic transmission. 
 
     
     
       3. A valve system for a hydraulic emergency driving gear function of a motor vehicle automatic transmission, comprising:
 a position valve ( 104 ) with a first piston slide ( 120 ); 
 an electromagnetic pressure regulator ( 86 ) having a decreasing characteristic curve; 
 a third clutch valve ( 13 ) with a first clutch valve slide ( 14 ); and 
 at least one fourth clutch valve ( 16 ) with a second clutch valve slide ( 17 ), 
 wherein the first piston slide ( 120 ) is movable into a first position and into a second position, and the first piston slide ( 120 ) is preloaded in the first position, 
 wherein, when the first piston slide ( 120 ) is in the second position, the electromagnetic pressure regulator ( 86 ) is configured for connecting a system pressure-carrying line ( 18 ) of the motor vehicle automatic transmission to at least one first emergency driving gear clutch ( 12 ) of the motor vehicle automatic transmission and to a second emergency driving gear clutch ( 15 ) of the motor vehicle automatic transmission such that the first emergency driving gear clutch ( 12 ) and the second emergency driving gear clutch ( 15 ) are actuated to engage an emergency driving gear of the motor vehicle automatic transmission, 
 wherein the first clutch valve slide ( 14 ) and the second clutch valve slide ( 17 ) are each moveable into a respective first position and into a respective second position, and the first clutch valve slide ( 14 ) and the second clutch valve slide ( 17 ) are each preloaded in the respective first position, and 
 wherein, when the first piston slide ( 120 ) is in the second position, the electromagnetic pressure regulator ( 86 ) is hydraulically connected at least to the third clutch valve ( 13 ) and to the fourth clutch valve ( 16 ) and is configured for hydraulically pressurizing the first clutch valve slide ( 14 ) and the second clutch valve slide ( 17 ) in a non-energized condition such that each of the first clutch valve slide ( 14 ) and the second clutch valve slide ( 17 ) move into the respective second position against the preload to connect the system pressure-carrying line ( 18 ) at least to the first emergency driving gear clutch ( 12 ) and to the second emergency driving gear clutch ( 15 ), whereby the first emergency driving gear clutch ( 12 ) and the second emergency driving gear clutch ( 15 ) are actuated to engage the emergency driving gear. 
 
     
     
       4. A valve system for a hydraulic emergency driving gear function of a motor vehicle automatic transmission, comprising:
 a position valve ( 104 ) with a first piston slide ( 120 ); 
 an electromagnetic pressure regulator ( 86 ) having a decreasing characteristic curve; and 
 an electromagnetic control valve ( 82 ), 
 wherein the first piston slide ( 120 ) is movable into a first position and into a second position, and the first piston slide ( 120 ) is preloaded in the first position, 
 wherein, when the first piston slide ( 120 ) is in the second position, the electromagnetic pressure regulator ( 86 ) is configured for connecting a system pressure-carrying line ( 18 ) of the motor vehicle automatic transmission to at least one first emergency driving gear clutch ( 12 ) of the motor vehicle automatic transmission and to a second emergency driving gear clutch ( 15 ) of the motor vehicle automatic transmission such that the first emergency driving gear clutch ( 12 ) and the second emergency driving gear clutch ( 15 ) are actuated to engage an emergency driving gear of the motor vehicle automatic transmission, 
 wherein the electromagnetic control valve ( 82 ) is hydraulically connected to the position valve ( 104 ) and configured for hydraulically pressurizing the first piston slide ( 120 ) in an energized condition such that the first piston slide ( 120 ) moves into the second position against the preload. 
 
     
     
       5. The valve system of  claim 4 , further comprising a hydraulic OR valve ( 85 ), the OR valve ( 85 ) configured for hydraulically connecting either the first emergency driving gear clutch ( 12 ) or the second emergency driving gear clutch ( 15 ) to the position valve ( 104 ) such that the first piston slide ( 120 ) is held in the second position when the electromagnetic control valve ( 82 ) is in a non-energized condition and does not hydraulically pressurize the first piston slide ( 120 ). 
     
     
       6. A valve system for a hydraulic emergency driving gear function of a motor vehicle automatic transmission, comprising:
 a position valve ( 104 ) with a first piston slide ( 120 ); 
 an electromagnetic pressure regulator ( 86 ) having a decreasing characteristic curve; 
 a parking lock valve ( 107 ), 
 wherein the first piston slide ( 120 ) is movable into a first position and into a second position, and the first piston slide ( 120 ) is preloaded in the first position, 
 wherein, when the first piston slide ( 120 ) is in the second position, the electromagnetic pressure regulator ( 86 ) is configured for connecting a system pressure-carrying line ( 18 ) of the motor vehicle automatic transmission to at least one first emergency driving gear clutch ( 12 ) of the motor vehicle automatic transmission and to a second emergency driving gear clutch ( 15 ) of the motor vehicle automatic transmission such that the first emergency driving gear clutch ( 12 ) and the second emergency driving gear clutch ( 15 ) are actuated to engage an emergency driving gear of the motor vehicle automatic transmission, 
 wherein the electromagnetic pressure regulator ( 86 ) is configured for actuating the parking lock valve ( 107 ) when the first piston slide ( 120 ) is in the first position. 
 
     
     
       7. The valve system of  claim 2 , further comprising at least a first clutch valve ( 9 ) or a second clutch valve ( 11 ) for actuating a further clutch ( 8 ,  10 ) for engaging non-emergency driving gears of the motor vehicle automatic transmission, wherein the valve system is configured for connecting the first clutch valve ( 9 ) or the second clutch valve ( 11 ) to the system pressure-carrying line ( 18 ) when the first piston slide ( 120 ) and the second piston slide ( 133 ) are both in the first position, respectively. 
     
     
       8. The valve system of  claim 1 , further comprising at least a first clutch valve ( 9 ) or a second clutch valve ( 11 ) for actuating a further clutch ( 8 ,  10 ) for engaging non-emergency driving gears of the motor vehicle automatic transmission, wherein the first clutch valve ( 9 ) or the second clutch valve ( 11 ) is permanently connected to the system pressure-carrying line ( 18 ). 
     
     
       9. The valve system of  claim 1 , wherein the electromagnetic pressure regulator ( 86 ) is configured for building up a hydraulic pressure in a spring chamber ( 262 ) of the position valve ( 204 ) to increase the preload force holding the first piston slide ( 220 ) in the first position. 
     
     
       10. The valve system of  claim 9 , wherein the spring chamber ( 362 ) is connected via at least one orifice ( 66 ) to an unpressurized tank such that the hydraulic pressure within the spring chamber ( 362 ) is lowerable to a lower pressure level. 
     
     
       11. The valve system of  claim 10 , wherein an orifice ( 74 ) is arranged in a line ( 359 ) between the spring chamber ( 362 ) and the electromagnetic pressure regulator ( 86 ). 
     
     
       12. The valve system of  claim 1 , wherein:
 the electromagnetic pressure regulator ( 86 ) is hydraulically connected to a fourth port ( 561 ) of the position valve ( 504 ); 
 an eleventh line ( 68 ) and at least one clutch valve ( 13 ,  16 ,  21 ) of an emergency driving gear clutch ( 12 ,  15 ,  19 ) are connected to a third port ( 559 ) of the position valve ( 504 ); 
 the third port ( 559 ) also connected to a tank line ( 567 ) via a second pressure divider orifice ( 537 ); 
 in the second switching position of the first piston slide ( 520 ), the third port ( 559 ) is connected to the fourth port ( 561 ) such that, during a pressurization of the third line ( 529 ) by the electromagnetic pressure regulator ( 86 ), a flow forms from the electromagnetic pressure regulator ( 86 ) to the tank line ( 567 ); and 
 due to pressure losses at a first pressure divider orifice ( 526 ) and the second pressure divider orifice ( 537 ), the pressure in the eleventh line ( 68 ) is lower than the pressure between the electromagnetic pressure regulator ( 86 ) and the first pressure divider orifice ( 526 ). 
 
     
     
       13. The valve system of  claim 12 , wherein a third pressure divider orifice ( 691 ) is arranged at least between one of the clutch valves ( 13 ,  16 ,  21 ) of the emergency driving gear clutches ( 12 ,  15 ,  19 ) and a certain port of a fifth clutch valve ( 690 ), and a fourth pressure divider orifice ( 692 ) is arranged between the certain port of the fifth clutch valve ( 690 ) and an evacuation or a tank such that the pressure in the certain port of the fifth clutch valve ( 690 ) is less than in at least one of the clutch valves ( 13 ,  16 ,  21 ) of the emergency driving gear valves ( 12 ,  15 ,  19 ). 
     
     
       14. The valve system of  claim 13 , wherein the fifth clutch valve ( 690 ) is configured for adjusting the pressure in a separating clutch (K 0 ). 
     
     
       15. A method for diagnosing a valve system for a hydraulic emergency driving gear function of a motor vehicle automatic transmission, the valve system includes a position valve ( 104 ) with a first piston slide ( 120 ) and an electromagnetic pressure regulator ( 86 ) having a decreasing characteristic curve, the first piston slide ( 120 ) is movable into a first position and into a second position, the first piston slide ( 120 ) is preloaded in the first position, the electromagnetic pressure regulator ( 86 ) is configured for connecting a system pressure-carrying line ( 18 ) of the motor vehicle automatic transmission to at least one first emergency driving gear clutch ( 12 ) of the motor vehicle automatic transmission and to a second emergency driving gear clutch ( 15 ) of the motor vehicle automatic transmission when the first piston slide ( 120 ) is in the second position such that the first emergency driving gear clutch ( 12 ) and the second emergency driving gear clutch ( 15 ) are actuated to engage an emergency driving gear of the motor vehicle automatic transmission, the method comprising:
 starting from a parking lock position (P), increasing the pressure output by the electromagnetic pressure regulator ( 86 ); and 
 when a measured speed ratio (nue=nT/nP) at the torque converter is unequal to zero after exiting the parking lock position (P) and increasing a clutch pressure acting on the parking lock valve ( 107 ) in a disengaging manner, performing a check based on a signal of a parking lock sensor to determine whether the first piston slide ( 120 ) is in the first switching position. 
 
     
     
       16. A method for diagnosing a valve system for a hydraulic emergency driving gear function of a motor vehicle automatic transmission, the valve system includes a position valve ( 104 ) with a first piston slide ( 120 ) and an electromagnetic pressure regulator ( 86 ) having a decreasing characteristic curve, the first piston slide ( 120 ) is movable into a first position and into a second position, the first piston slide ( 120 ) is preloaded in the first position, the electromagnetic pressure regulator ( 86 ) is configured for connecting a system pressure-carrying line ( 18 ) of the motor vehicle automatic transmission to at least one first emergency driving gear clutch ( 12 ) of the motor vehicle automatic transmission and to a second emergency driving gear clutch ( 15 ) of the motor vehicle automatic transmission when the first piston slide ( 120 ) is in the second position such that the first emergency driving gear clutch ( 12 ) and the second emergency driving gear clutch ( 15 ) are actuated to engage an emergency driving gear of the motor vehicle automatic transmission, the method, comprising:
 starting from a driving position (D), following a particular diagnostic path depending on whether a driver demand for an engagement corresponds to a parking lock position (P) or not; 
 as part a first diagnostic path in response to a demand for the parking lock position (P) after evacuation of at least one emergency driving gear clutch ( 12 ,  15 ) and the electromagnetic control valve ( 82 ) and after increasing the pressure output by the electromagnetic pressure regulator ( 86 ), performing a check based on a signal of a parking lock sensor to determine whether the first piston slide ( 120 ) is in the first switching position; and 
 as part a second diagnostic path in response to a demand other than for the parking lock position (P) after engagement of a certain driving position (D 6 ) and after increasing the pressure of the emergency driving gear clutch ( 12 ,  15 ) above a control pressure of the position valve ( 104 ) and after increasing the pressure output by the electromagnetic pressure regulator ( 86 ) and after evacuating at least one emergency driving gear clutch ( 12 ,  15 ), performing a check of a set transmission ratio in the motor vehicle automatic transmission to determine whether the first piston slide ( 120 ) is in the first switching position. 
 
     
     
       17. A method for diagnosing the valve system of  claim 1 , comprising:
 starting from a parking lock position (P), increasing the pressure output by the electromagnetic pressure regulator ( 86 ); and 
 when a measured speed ratio (nue=nT/nP) at the torque converter is unequal to zero after engaging a certain driving position (D 6 ) and after increasing the pressure output by the electromagnetic pressure regulator ( 86 ) and after evacuating the emergency driving gear clutches ( 12 ,  15 ,  19 ), performing a check to determine whether the certain driving position (D 6 ) is engaged as an emergency driving gear step, 
 wherein a positive check establishes that the piston slide ( 520 ) of the position valve ( 504 ) is correctly in the second switching position. 
 
     
     
       18. A motor vehicle automatic transmission, comprising the valve system of  claim 1 . 
     
     
       19. A motor vehicle, comprising the motor vehicle automatic transmission of  claim 18 .